Accused Tucson gunman Jared Loughner had several encounters with Arizona police before Saturday's shooting, including getting arrested when he was 17 for drinking so much vodka that his school sent him to a hospital emergency room.

"[Loughner] advised that he drank the alcohol because he was very upset as his father yelled at him," according to the May 2006 Pima County Sheriff's office police report obtained by ABC News. "I could see his eyes were very red and he was crying...I was advised that he had stolen the alcohol from his father's liquor cabinet."

School officials told authorities that they'd sent Loughner to the hospital because he was "so extremely intoxicated." Nurses later estimated that Loughner had consumed approximately 250 milliliters of vodka. He was charged with charged as a minor with possession of alcohol.

Pima County Sheriff's officers had contact with Loughner or his family at least 10 times in the past several years for incidents that included reports of vandalism of the family's property, possession of drug paraphernalia charges, and an altercation Loughner had with a classmate who pricked him with a needle. Loughner was 15 at the time of the needle incident and he declined to press charges, according to the report.

In the other incidents, the Loughner family called authorities because they claimed to have been victims of crimes ranging from vandalism to identity theft.

Earlier today it was revealed that Loughner had an altercation with his father on Saturday, just hours before he allegedly opened fire in a grocery story parking lot where six people died and 14 were wounded.

Loughner's father saw him take a black bag out of a car trunk. When the father approached, his mumbling son took off running and the father chased him in his car, investigators said. Police haven't said what was in the bag, but they continue to search for it.

Also that morning, Loughner was stopped by police after running a red light.

When the officer determined that there were no outstanding warrants for Loughner, he was allowed to proceed to his destination with a warning to drive carefully.

Loughner was stopped at approximately 7:30 a.m. on Saturday by an Arizona Game and Fish Department officer, according to a statement released by the department.

"They do not routinely make traffic stops, except when public safety is at risk, such as running a red light," read the statement. "The officer took Mr. Loughner's driver's license and vehicle registration information and ran it through dispatch. The check came back with no wants nor any outstanding warrants on either the subject or his vehicle."

Later that morning, at 10:11 a.m., Loughner allegedly shot Rep. Gabrielle Giffords in the head and sprayed the crowd around her with rounds from a 9mm Glock handgun.

Investigators tell ABC News they are reviewing these past interactions Loughner had with police to determine whether the massacre could have been prevented.

Immediately after the assault on Giffords and 19 others who attended her sidewalk meeting, Dupnik said that Loughner had never been on his department's radar.

He did say, however, "There have been law enforcement contacts with individuals where he made threats...to kill."

Loughner was booked by police once in 2007 for possession of drug paraphernalia and was cited in 2008 for graffiti, according to public records and media reports.

Loughner, 22, was also suspended from Pima Community College in October 2010 after he violated the school's conduct code by taping a YouTube video on campus that accused the school of being "unconstitutional." Loughner ended up withdrawing from the school.

According to Loughner's college records, on Sept. 29, an officer who delivered the suspension letter to Loughner's home where he was met by Loughner and his father, Randy. The report says Loughner "held a constant trance of staring as I narrated the past events that had transpired," and kept that stony silence for an hour until he finally said, "I realize now that this is all a scam."

In May 2010 a teacher reported Loughner became "very hostile" when he learned he was received a "B" in his Pilates class. The teacher told campus police that Loughner "threw his work down" and said the grade was "unacceptable."

The teacher also told authorities that she worried that a conversation with Loughner after class might "become physical."

And in September 2010, two campus cops took Loughner to see a counselor, after which a report was written to say that "there might be a mental health concern involved with Loughner."

Classes that Loughner took between 2005 and 2010, when he withdrew from school, included "Tai Chi for Beginners," "Country Swing in a Nutshell," "Yoga," "Meditation" and a course listed as "Making Career Choices."

He was also enrolled in several more traditional courses such as "Introduction to Sociology," and the "Natural History of the Southwest."

A high school friend of the accused gunman dismissed speculation that Loughner's alleged rampage was sparked by political passion.

"He did not watch TV, he disliked the news," Zach Osler said. "He didn't listen to political radio, he didn't take sides, he wasn't on the left, he wasn't on the right."

Osler said that Loughner was angry at the world.

"He wasn't shooting people, he was shooting at the world," the friend said.

Friend of Jared Loughner Said Suspect Used Drugs Frequently

"I wish I could have helped him. ... I just forgot about him, you know," Osler said. "We stopped talking to each other. I wish there was something I could have did or said to help him or try to get him help. I just didn't, so that's why it's hard to look at the picture of him. It looks like a monster."

Loughner was arraigned at a federal court in Phoenix Tuesday on charges related to the deadly shooting that has left Giffords in intensive care. Giffords remains in critical condition, but doctors are optimistic about her recovery. She is now able to breathe on her own.

Loughner's downward spiral and increasing anger began after a high school girlfriend, Kelsey Hawkes, broke up with him, Osler said.

Hawkes, in a statement released to the Los Angeles Times said, "'I did date Jared Loughner six years ago in high school but he's not the same Jared Loughner that the world now knows as a mass murderer -- not the same person at all.'

As a teenager, Loughner turned to heavy drinking and drugs, such as the legal hallucinogen salvia, Osler said.

"He would say he was using it, and he would talk about it and say what [it] would do to him and I was like, 'Dude, that's screwed up.'"

Osler described the Loughner family home as uninviting.

"The house itself is kind of shrouded, it's covered up ... like cold, cold dark unpleasant. ... I always felt unwelcome, always, like I shouldn't be there," Osler said.

Loughner's parents, Randy and Amy Loughner, did not attend their son's arraignment. Instead, the devastated parents issued a statement Tuesday, saying they "don't understand" what prompted their son to allegedly go on a "heinous" shooting rampage.

"This is a very difficult time for us. We ask the media to respect our privacy," according to the statement. "There are no words that can possibly express how we feel. We wish that there were, so we could make you feel better. We don't understand why this happened.

"It may not make any difference, but we wish that we could change the heinous events of Saturday. We care very deeply about the victims and their families. We are so very sorry for their loss."

It was the first word from Loughner's family since the carnage on Saturday.

The Loughners' note of confusion and contrition contrasted with a hateful scribble that was found in the Loughner home that simply read "Die bitch," a sheriff's official told The Associated Press. Other notes in the safe included "I planned ahead," "My assassination" and the name "Giffords."

The Loughner family home.

Loughner's parents have sealed themselves in their suburban Tucson home since Saturday's shooting, blocking access to the front door with a piece of wood to presumably keep people off their property.

Osler pointed to an online documentary series called "Zeitgeist" as a possible influence on the man.

The series rails on currency-based economics.

"I really think that this 'Zeitgeist' documentary had a profound impact on Jared's mindset and how he viewed that world that he lives in," Osler said.

Osler also said that Loughner's favorite quote was "Out of chaos breathes creation."

Loughner ended his friendship with Osler through a text message two years ago, writing to him, "I don't want to be friends with you anymore."

"I forgot about Jared. I stopped thinking about this kid because thinking about him wasn't something I wanted to do," Osler said.

As Osler comes to terms with Loughner's descent, family members and supporters of the victims in the shooting will gather for a memorial today that Obama will lead.

Obama Heads to Memorial for Shooting Victims

The president worked overnight tinkering with the speech that his staff has been working on for days, sources told ABC News.

The speech is not expected to be political but rather about lifting the nation's spirits up, sources said.

Two church services were held for the victims Tuesday night.

Several hundred mourners filled a Tucson Catholic church for a public Mass. As people filed in, nine young girls sang "Amazing Grace."

"I know she is singing with us tonight," Tucson Bishop Gerald Kicanas told The Associated Press.

Today, Ben Heilman, the husband of the woman who took Christina to the political event that turned tragic, described Christina's relationship with his wife as a natural match.

"Christina is a very bright young girl who seemed to have a special propensity for engaging with adults, and my wife is a very playful older woman who had propensity for engaging with younger kids," Heilman said.

Heilman said that his wife, Suzie Heilman, is recovering from surgery on her shattered hip. She suffered gunshot wounds to her torso and a broken hip. Amid her pain, Suzie Heilman continues to cry out for Christina.

"When she kind of comes out of those semi-dream, twilight states, she is very vocal with tidbits that come sentence by sentence," Heilman said. "She's reliving things in her mind. She calls out for Christina, she talks about the impact of the bullets and that dramatic sense of bleeding out on the ground."

Heilman said Christina's parents have reached out to him, sending him e-mails and talking by phone.

"That is one of the more mind boggling aspects of this, the level of grace that the Greens have shown for what we're going through is above and beyond. ... We shouldn't lose our babies this way," Ben Heilman said.

Pam Simon, one of two staffers for Giffords who was hospitalized with injuries, is almost fully recovered, her son said.

"We're very happy that she's recovering so well, but I do need to acknowledge we feel very fortunate," Fritz Simon said. "A lot of people were hurt on Saturday, and a lot of lives were destroyed."

Simon said that his mom did see the shooter, and he thanked a good Samaritan who helped save his mother.

"I know that after she was hit. She lay face-down and tried to keep still, but there was a Samaritan that came along and stayed with her. He said he's going to stay with her, and he took her cell phone and called my father," Simon said.

The memorial, "Together We Thrive, Tucson and America," will take place on the University of Arizona's campus at 6 p.m. MT.

ABC News' Devin Dwyer, Tonya Kerr and Desiree Adib contributed to this report, as well as The Associated Press.